<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        <input type="" name="" id="" value="" />
        <script type="text/javascript">
            var search =document.querySelector('input');
            document.addEventListener('keyup',function(e) {
                if (e.keyCode == 83) {
                    search.focus();
                }
            })
        </script>
    </body>
</html>
